readutil library support

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1680 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

C/readutil.c

@@ -0,0 +1,169 @@
+/*************************************************************************
+*									 *
+*	 YAP Prolog 							 *
+*									 *
+*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
+*									 *
+* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
+*									 *
+**************************************************************************
+*									 *
+* File:		readutil.c						 *
+* Last rev:	2/8/06							 *
+* mods:									 *
+* comments:	readutil library support				 *
+*									 *
+*************************************************************************/
+#ifdef SCCS
+static char SccsId[] = "%W% %G%";
+#endif
+
+#include "Yap.h"
+#include "Yatom.h"
+#include "Heap.h"
+#include "yapio.h"
+#include "iopreds.h"
+
+static Int
+rl_to_codes(Term TEnd, int do_as_binary, int arity)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "read_line_to_codes/2");
+  Int status;
+  UInt max_inp, buf_sz, sz;
+  char *buf;
+  int  binary_stream;
+
+  if (sno < 0)
+    return FALSE;
+  status = Stream[sno].status;
+  binary_stream = Stream[sno].status & Binary_Stream_f;
+  if (status & Eof_Stream_f) {
+    UNLOCK(Stream[sno].streamlock);
+    Yap_Error(PERMISSION_ERROR_INPUT_PAST_END_OF_STREAM, ARG1, "read_line_to_codes/%d", arity);
+    return FALSE;
+  }
+  max_inp = (ASP-H)/2-1024;
+  buf = (char *)TR;
+  buf_sz = (char *)Yap_TrailTop-buf;
+  while (TRUE) {
+    if ( buf_sz > max_inp ) {
+      buf_sz = max_inp;
+    }
+    if (do_as_binary && !binary_stream)
+      Stream[sno].status |= Binary_Stream_f;
+    sz = Stream[sno].stream_gets(sno, buf_sz, buf);
+    if (do_as_binary && !binary_stream)
+      Stream[sno].status &= ~Binary_Stream_f;
+    if (sz == -1 || sz == 0) {
+      UNLOCK(Stream[sno].streamlock);
+      if (Stream[sno].status & Eof_Stream_f) {
+	return Yap_unify_constant(ARG2, MkAtomTerm (AtomEof));
+      }
+      return FALSE;
+    }
+    if (Stream[sno].status & Eof_Stream_f || buf[sz-1] == 10) {
+      /* we're done */
+      Term end;
+      UNLOCK(Stream[sno].streamlock);
+      if (!(do_as_binary || Stream[sno].status & Eof_Stream_f)) {
+	buf[sz-1] = '\0';
+      }
+      if (arity == 2)
+	end = TermNil;
+      else
+	end = Deref(XREGS[arity]);
+      return Yap_unify(ARG2, Yap_StringToDiffList((char *)TR, end)) ;
+    }
+    buf += (buf_sz-1);
+    max_inp -= (buf_sz-1);
+    if (max_inp <= 0) {
+      UNLOCK(Stream[sno].streamlock);
+      Yap_Error(OUT_OF_STACK_ERROR, ARG1, "read_line_to_codes/%d", arity);
+      return FALSE;      
+    }
+  }
+}
+
+static Int
+p_rl_to_codes(void)
+{
+  return rl_to_codes(TermNil, FALSE, 2);
+}
+
+static Int
+p_rl_to_codes2(void)
+{
+  return rl_to_codes(TermNil, TRUE, 3);
+}
+
+static Int
+p_stream_to_codes(void)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "read_line_to_codes/2");
+  CELL *HBASE = H;
+
+  if (sno < 0)
+    return FALSE;
+  while (!(Stream[sno].status & Eof_Stream_f)) {
+    /* skip errors */
+    Int ch = Stream[sno].stream_getc(sno);
+    if (ch == EOFCHAR)
+      break;
+    *H++ = MkIntTerm(ch);
+    *H = AbsPair(H+1);
+    H++;
+    if (H >= ASP) {
+      Yap_Error(OUT_OF_STACK_ERROR, ARG1, "read_stream_to_codes/3");
+      return FALSE;      
+    }
+  }
+  if (H == HBASE)
+    return Yap_unify(ARG2,ARG3);
+  H[-1] = Deref(ARG3);
+  return Yap_unify(AbsPair(HBASE),ARG2);
+}
+
+static Int
+p_stream_to_terms(void)
+{
+  int sno = Yap_CheckStream (ARG1, Input_Stream_f, "read_line_to_codes/2");
+  Term t = Deref(ARG3);
+
+  if (sno < 0)
+    return FALSE;
+  while (!(Stream[sno].status & Eof_Stream_f)) {
+    /* skip errors */
+    TokEntry *tokstart = Yap_tokptr = Yap_toktide = Yap_tokenizer(sno);
+    if (!Yap_ErrorMessage)
+    {
+      Term th = Yap_Parse();
+      if (H >= ASP-1024) {
+	Yap_Error(OUT_OF_STACK_ERROR, ARG1, "read_stream_to_terms/3");
+	return FALSE;      
+      }
+      if (!th || Yap_ErrorMessage)
+	break;
+      if (th == MkAtomTerm (AtomEof)) {
+	Yap_clean_tokenizer(tokstart, Yap_VarTable, Yap_AnonVarTable);
+	return Yap_unify(t,ARG2);
+      } else {
+	t = MkPairTerm(th,t);
+      } 
+    }
+    Yap_clean_tokenizer(tokstart, Yap_VarTable, Yap_AnonVarTable);
+  }
+  return Yap_unify(t,ARG2);
+}
+
+void
+Yap_InitReadUtil(void)
+{
+  Term cm = CurrentModule;
+  CurrentModule = READUTIL_MODULE;
+  Yap_InitCPred("read_line_to_codes", 2, p_rl_to_codes, SafePredFlag|SyncPredFlag);
+  Yap_InitCPred("read_line_to_codes", 3, p_rl_to_codes2, SafePredFlag|SyncPredFlag);
+  Yap_InitCPred("read_stream_to_codes", 3, p_stream_to_codes, SafePredFlag|SyncPredFlag);
+  Yap_InitCPred("read_stream_to_terms", 3, p_stream_to_terms, SafePredFlag|SyncPredFlag);
+  CurrentModule = cm;
+}
+